1. Field of Invention
The present invention relates to an optical printer head employing a phosphor for emitting light and, more particularly, to an optical printer head which is equipped with a recording device that records data output from a computer on a recording sheet.
2. Description of Related Art
Conventionally, a recording device employing an optical printer head is known. Optical printer heads employ such means as polygon mirrors, galvanno mirrors, liquid crystal shutter arrays, LED arrays or vacuum fluorescent display devices to form a latent image on a photoconductive material.
Optical printer heads employing polygon mirrors or galvanno mirrors, for example, as shown in U.S. Pat. No. 4,847,492, employ a large optical system for scanning and condensing a light beam emitted by single light source on the photoconductive material. Optical printer heads employing a liquid crystal shutter array exhibit difficulties in forming latent images having sufficient contrast on the photoconductive material, so that the image formed on a recording medium does not have sufficient contrast. Optical printer heads employing an LED array have low production efficiencies.
Optical printer heads having a liquid crystal shutter array, an LED array or a fluorescent display device must include an optical system, such as the roof mirror lens array, or a self focus lens, which focuses light on a photoconductive material. As a result, such optical printer heads have complicated structures. When roof mirror lens arrays or self focus lens arrays are used, long optical distance is required to focus light on the photoconductive material through the lens. Therefore the optical printer head has large size.